Modern bathtubs have a drain opening and an overflow opening. The drain opening is positioned at the lowest point in a bathtub bottom wall, and allows water to be drained from the bathtub when it is no longer needed. The overflow opening is positioned in a bathtub end wall, usually below the taps, and allows for excess water to drain from the bathtub when it is overfilled. While drain openings often are set in the bathtub bottom walls so as to be level with the ground, overflow openings are often set in line with the slope of the bathtub end walls, which often extend upwardly from the bathtub bottom walls at a non-vertical angle.
Drain and overflow openings are typically connected to household waste plumbing with drain and overflow fittings, which attach sealingly to the respective drain and overflow openings, and conduits which connect the drain and overflow fittings to the household waste water plumbing. Recently innovative manufacturers have provided the drain fittings, overflow fittings, and conduits together and sold them as a kit, along with other plumbing fittings and trim fittings, such as for example faceplates and drain baskets.
There have been numerous attempts at overcoming problems associated with prior art bathtub drain and overflow kits.
Bathtubs come in a variety of designs. The relative positions of drain and overflow openings often vary from bathtub to bathtub. Similarly, the slope of bathtub end walls varies from bathtub to bathtub as does the size of the overflow openings. Both the slope of the bathtub end wall and the location of the overflow opening create challenges for the creation of bathtub drain and overflow kits that can be used on more than one bathtub design. The various differences in bathtub designs has therefore required manufacturers to make bathtub overflow kits specific to the several different bathtub designs, which is burdensome for resellers who need to stock several different kits. Furthermore, if fixed fittings are used between the overflow opening and the drain, then stress will be added to the system, particularly if force is required to connect the fittings between the drain and overflow opening. Often fittings will be connected together permanently using solvent cement.
U.S. Pat. No. 6,886,193 (McAlpine) discloses one attempt at overcoming the problem of the relative alignment of the overflow and the drain. McAlpine discloses an overflow head which is connected to a down pipe by a ball and socket joint. The ball and socket joint in McAlpine allows for relative alignment of the overflow head and the outlet. However, McAlpine teaches fixing the ball and socket joint to retain its position after the installation. A problem with the McAlpine overflow head is that it requires a cumbersome brass circular nut to secure the joint together. The preferred form of the McAlpine bath waste is said to have the nut fixed or “factory sealed” onto the joint, using glue or welding, to prevent users from disassembling the joint. The tightness of the fixed nut is sufficient to permit a degree of movement of the ball and socket joint, to allow the relative alignment of the head and outlet to be adjusted. However, a failure to properly tighten the brass circular nut can cause problems. For example, if the brass nut is not sufficiently tightened, the joint may leak. On the other hand if the brass nut is overtightened the joint may become a fixed joint, which is undesirable because it can add stress to the system. The use of welding or glue can also cause the joint to become a fixed joint. The McAlpine bath waste is also susceptible to leaking from the joint loosening over time from repetitive expansions and contractions of the joint and the pipes connected to it, in response to cycles of hot bath water draining through the system.
Furthermore, it is common for municipal plumbing codes to require plumbing joints that are located in an inaccessible location, such as inside a wall or floor, to be permanent. This means that a detachable connection between the drain and overflow openings is not permitted by most municipal plumbing codes since it is not a permanent connection.
Another problem with the variability of bathtub designs is that the variability in bathtub end wall slopes creates challenges for properly aligning and installing the sealing gaskets at the overflow openings. The problem of properly installing overflow gaskets also arises in those cases where different bathtubs have different sizes of overflow openings. Prior bathtub drain and overflow kits often have overflow gaskets that are difficult to fix into place during assembly of the overflow fitting. The prior art gaskets are often disc-shaped washer-type seals that are held in place through pressure, which means that misalignment can occur easily. Proper sealing of the overflow gasket often requires the gasket to be properly centered with respect to the overflow opening. Misalignment of the gasket at the overflow opening will result in a leaking connection.
Another problem with prior art bathtub drain and overflow fittings is that different gasket designs are required depending on whether it is used for a drain opening or an overflow opening. This problem arises because the openings in the bathtub walls are generally different sizes for the drain and the overflow. For example, U.S. Pat. No. 2,880,425 (Lengyel) discloses a drain apparatus which has an interposed sealing gasket for sealing the overflow opening. The sealing gasket is shown having a slanted portion which seals against the bath tub. However, Lengyel discloses two separate gaskets for the overflow opening and the drain opening. This means that separate seals must be specifically designed for each of the openings. Furthermore, if replacement parts are required, for example, if a gasket is lost or damaged, a different gasket part would be required depending on whether the replacement part is to be connected to the overflow opening or the drain opening. Moreover, this means that if a drain and overflow kit is sold with replacement pieces, different replacement gaskets would be required for each of the drain and overflow openings, adding to the complexity of the system.
Other prior art patents of general interest in the field of plumbing connections and fittings include:                Canadian Patent No. 2,338,814 (Marsden et al.);        U.S. Pat. No. 1,883,609 (Dennis), U.S. Pat. No. 2,477,478 (Donahue), U.S. Pat. No. 2,556,659 (Patterson), U.S. Pat. No. 2,599,767 (Long), U.S. Pat. No. 3,123,367 (Brummer et al.), U.S. Pat. No. 3,334,774 (Poltorak), U.S. Pat. No. 3,355,181 (Olson), U.S. Pat. No. 3,490,776 (Avery), U.S. Pat. No. 3,680,153 (Haldopoulos et al.), U.S. Pat. No. 3,695,646 (Mommsen), U.S. Pat. No. 3,701,452 (Tonn), U.S. Pat. No. 3,712,645 (Herter), U.S. Pat. No. 3,931,992 (Coel), U.S. Pat. No. 3,997,197 (Marsh et al.), U.S. Pat. No. 4,077,656 (Swindler), U.S. Pat. No. 4,298,219 (Amelink), U.S. Pat. No. 4,418,922 (Janzito), U.S. Pat. No. 4,560,174 (Bisi), U.S. Pat. No. 4,778,189 (Udagawa), U.S. Pat. No. 4,834,395 (Benford), U.S. Pat. No. 5,390,939 (Terauchi et al.), U.S. Pat. No. 5,626,520 (Mazziotti), U.S. Pat. No. 6,058,525 (Paden), U.S. Pat. No. 6,295,664 (Fritz et al.), U.S. Pat. No. 6,415,463 (Slothower), U.S. Pat. No. 6,484,331 (Minnick), U.S. Pat. No. 6,681,420 (Ball), U.S. Pat. No. 6,687,926 (Bayley), U.S. Pat. No. 6,859,956 (Mantyla et al.), U.S. Pat. No. 7,121,556 (Barth et al.), U.S. Pat. No. 7,197,777 (Ismert et al.), U.S. Pat. No. 7,237,280 (Holden, Jr. et al.), and U.S. Pat. No. 7,866,670 (Dhole et al.); and        U.S. Patent Application Publication Nos. 2002/0032926 (Lewis), 2003/0126676 (Gallacher et al.), 2004/0117907 (Ball), 2008/0155745 (Burr), 2008/0216229 (Johannes), 2009/0249542 (Uhl), 2009/0260154 (Shoop et al.).        
Therefore there is a continuing need for improvement in the design of bathtub drain and overflow fitting kits.